Revisiting Beta: How Well Has Beta Predicted Returns?

After the capital asset pricing mannequin (CAPM) was developed within the Sixties and Nineteen Seventies, monetary researchers began to check how properly this theoretical mannequin truly labored in the actual world.

Amid increasing computing energy and higher information entry, the Nineteen Eighties turned a crucial period for gauging CAPM’s validity as analysts explored beta’s effectiveness in anticipating future returns. 

Surprisingly, the overall consensus that emerged was that beta’s return forecasting energy was fairly weak.

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Within the 60 years or so since CAPM emerged, how properly has the mannequin and beta anticipated returns over the a long time? To seek out out, we analyzed each agency that has traded on the NYSE and NASDAQ and constructed portfolios of corporations based mostly on their systematic danger (beta) utilizing month-to-month returns and a 12-month rolling calculation.

If a agency had a beta beneath 0.5, it was allotted to the low beta portfolio. Companies with beta higher than 1.5 had been allotted to its excessive beta counterpart.

Utilizing these groupings, we examined how the portfolios carried out over the following 12 months — each on a median and market-cap-weighted foundation. Portfolios had been then reconstructed in accordance with new beta calculations every year.


Excessive-Beta Portfolio Median Return Low-Beta Portfolio Median Return Excessive-Beta Portfolio Market-Weighted Return Low-Beta Portfolio Market-Weighted Return P.c of Years in Accordance with CAPM
Nineteen Seventies 14.9% 2.5% 14.3% 3.5% 80%
Nineteen Eighties 13.0% 14.4% 12.1% 18.1% 40%
Nineteen Nineties 18.7% 12.6% 22.6% 13.4% 70%
2000s 15.2% 8.9% 10.7% 5.2% 80%
2010s 14.7% 9.0% 13.3% 12.5% 91%

It seems, the Nineteen Eighties had been a horrible time for beta. On an annualized foundation, a low beta portfolio carried out 6 share factors higher on common than its excessive beta counterpart over the last decade, producing an 18.14% vs. a 12.12% return

We then examined the proportion of years that mirrored CAPM predictions on an ordinal foundation all through the last decade. In solely 4 out of the ten years did CAPM precisely forecast returns. That’s, optimistic market return years ought to correspond to excessive beta beating low beta portfolios and detrimental market return years to low beta beating excessive beta portfolios. Which means CAPM did worse than a random stroll over this time interval and helps clarify why researchers of the period had been so skeptical of the mannequin.

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However the Nineteen Eighties had been one thing of an outlier. Because the a long time progressed, beta and CAPM turn into a greater predictor. From 2010 to 2020, CAPM was proper in 10 of the 11 years.

Certainly, in each decade because the Nineteen Eighties, a excessive beta portfolio generated barely greater than 5 share level premium over its low beta peer on an annualized foundation. That’s, the excessive beta portfolio averaged a 15.53% return in comparison with the low-beta’s 10.34% return.

All informed, the outcomes spotlight that beta isn’t as dangerous a predictor of future returns as is commonly thought. The Nineteen Eighties had been a horrible time for beta and CAPM, however since that decade, beta has been a good forecaster of future returns.

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All posts are the opinion of the writer. As such, they shouldn’t be construed as funding recommendation, nor do the opinions expressed essentially replicate the views of CFA Institute or the writer’s employer.

Picture credit score: ©Getty Photos / Eskay Lim / EyeEm


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Derek Horstmeyer

Derek Horstmeyer is a professor at George Mason College College of Enterprise, specializing in exchange-traded fund (ETF) and mutual fund efficiency. He presently serves as Director of the brand new Monetary Planning and Wealth Administration main at George Mason and based the primary student-managed funding fund at GMU.

Zach McKannan

Zach McKannan is a graduating senior at George Mason College along with his BS in finance. At Mason, he labored a semester as an analyst for the Montano Pupil Managed Funding Fund, concentrating within the know-how area. Following his commencement, McKannan might be working as an operations supervisor for Glenloch Authorized. As well as, he hopes to construct his personal monetary schooling enterprise.

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